Making sense ot the 3D View and aligning and rotating objects by specific values
dI solved this issue by selecting the camera and moving it to the cursor at world origin.  Then with the camera view open in another window I was able to move the camera along the X and Y axes until the model came into view (upside down!) and then rotate the camera until the model was the right way up - using the rotation properties box to specify the exact rotations - 90 / 180 / 180.
The Y axis alignment was done by eye - I could not find any way to centre the camera exactly on the centre of the model.
It will have to do...